Generally, a display device operates as an interface device that converts data generated by an information-processing device into an image.
The display device includes a cathode ray tube (CRT) display device, a liquid crystal display (LCD) device, an organic electro luminescent (EL) device, a plasma display panel (PDP) device etc. The CRT display device displays an image by controlling electron beams irradiated onto the fluorescent layer of the CRT screen. The LCD device displays an image using liquid crystal. The EL device displays an image through an organic light emitting layer that emits by a current supplied to the organic light emitting layer. The PDP displays an image by plasma.
The organic EL device has merits such as a lightweight, a small thickness, a high brightness, an excellent color-reappearance, a fast response speed, a capability of displaying a full color image, a low power consumption, a wide range of operational temperature, a low manufacturing cost in comparison with other display devices such as the LCD device.
The organic EL device includes anode electrodes, an organic layer, organic light emitting patterns, and a cathode electrode. The anode electrodes are disposed on a substrate in a matrix configuration, the organic layer is disposed on the substrate, and the organic layer has an opening that exposes the anode electrodes. The organic light-emitting patterns are disposed on the anode electrodes and emit light. The cathode electrode is disposed on the organic light-emitting patterns.
Conventional organic light-emitting patterns of the organic EL device have a multiple-layered structure. For example, the organic light-emitting patterns have a hole injection layer (HIL), an emission material layer (EML) formed on the HIL, and an electron injection layer (EIL) formed on the EIL.
The organic light-emitting patterns may be formed by various apparatus such as a slit mask processing apparatus, a spin coating processing apparatus, a vacuum deposition processing apparatus etc. Recently, the organic light-emitting patterns are formed by an ink-jet type drop filling device.
In forming the organic light-emitting patterns on the substrate, a speed of drying an organic light-emitting material of the organic light-emitting patterns is very important.
Generally, the organic light-emitting material includes a volatile solvent. When the light-emitting patterns is formed on the substrate by the ink-jet type drop filling device, the thickness of the organic light emitting-patterns are affected by the speed of drying the organic light emitting material. When the speed of drying the organic light emitting materials is locally different, the thickness of the organic light emitting-patterns may not be uniformly controlled so that a brightness uniformity of lights generated from the organic light emitting-patterns may not be uniformly controlled.
In order to overcome this problem, the droplet including organic material is formed on a non-effective display region disposed on an organic layer of the substrate as well as an effective display region, thereby forming dummy organic light-emitting patterns on the non-effective display region. The dummy organic light-emitting patterns adjust the speed of drying the organic light-emitting patterns formed on the effective display region.
However, the dummy organic light-emitting patterns disposed in the non-display region of the organic layer have a position higher than that of the organic light-emitting patterns in the display region by a thickness difference between the anode electrode and the organic layer. Therefore, a dummy organic material for forming the dummy organic light-emitting patters flows into the opening of the display region.
When the dummy organic material flows into the opening, the thickness of the organic light-emitting patters may not be controlled, so that the display quality of the image may be deteriorated.